The present invention relates to an arrangement for a gas spring consisting on the one hand of a cylinder closed at both ends by means of end walls with a piston capable of axial displacement inside a fluid-filled inner space of the cylinder, which piston divides the latter into two sub-spaces, of which the first sub-space is bounded by a first end wall, the piston and an interjacent part of the cylinder wall, and the second sub-space is bounded by the second end wall, in which a piston rod operatively connected to the piston is mounted in a sliding and sealing fashion, the piston and an interjacent part of the cylinder wall, and on the other hand of an enclosed space so arranged as to communicate with the aforementioned first sub-space via a first openable and closable valve.
A gas spring of the kind referred to above, which, after compression, exhibits a delayed return to its original length, is described in more detail in WO90/15267 (SE-B-462726). Also described in the aforementioned publication is an application for such a gas spring with a delayed return, namely for the purpose of ejecting a pressed component from a pressing tool.
Although a gas spring of the kind, referred to above has an entirely satisfactory function, there is a general wish to have available a gas spring with smaller installation dimensions for otherwise unchanged characteristics. A further wish is to have available a gas spring which operates exclusively with gas. The gas spring referred to by way of introduction, however, requires a gas/oil mixture; the use of gas alone in a gas spring according to WO90/15267 would permit the piston rod to execute undesirable overspringing movements.